1. Field of the Invention
The present invention relates to a projector-type vehicle lamp and, in particular, relates to a vehicle lamp in which a distribution light pattern irradiated upward of a cutoff line is generated.
2. Description of the Related Art
A projector-type headlamp is a lamp for a vehicle in which a light from a light source is reflected by a reflector and the reflected light is projected in the forward direction by a projection lens. If such projector-type headlamp is used for producing a low beam, a shade is provided between the projection lens and the reflector. The shade shields a part of the light reflected from the reflector so as not to irradiate the upward irradiation light from the projection lens. Therefore, a border line of contrast is formed as a cutoff line in the distribution light pattern.
According to such projector-type headlamp, since the upward irradiation light is almost completely removed, there arises a problem that a visibility of overhead signs (OHS) installed above a road surface in the forward direction of a vehicle degrades.
In order to solve such a problem, a projector-type headlamp disclosed in JP-A-2001-35218, for example, is provided with a protruded portion of a wedge shape at a portion near an upper end edge of a front face of a shade. The protruded portion has an upper tilted face which extends obliquely downward in the forward direction. A light reflected from an upper front end portion of a reflector enters into the upper tilted face of the protruded portion, and then, reflected by the upper tilted face of the protruded portion as an overhead sign irradiation light irradiating an upper portion of a cutoff line in the forward direction.
However, when the head lamp is configured to project a light in the forward direction from a single reflecting surface as disclosed in JP-A-2001-35218, it is required to secure the reflecting surface with a predetermined size or more in order to irradiate a light of a predetermined luminance or more uniformly over entire region of the overhead sign. Thus, it is difficult to miniaturize the headlamp. Particularly in the headlamp disclosed in JP-A-2001-35218, it is configured to reflect a light from a light source by the upper front end portion of the reflector forming a main distribution light, and then, the reflected light is again reflected at the portion near the upper end edge of the front face of a shade thereby to form an overhead sign irradiation light. Therefore, it is difficult to irradiate light of a predetermined luminance or more uniformly over the entire region of the overhead sign. Thus, some kind of improvement has been desired.